1. Field of the Invention
This invention relates to the field of composite photography and more particularly to a novel apparatus and method for producing a single, composite film strip having multiple image elements derived photographically at different times and places.
2. Brief Description of the Prior Art
Composite photography is described as the process of making pictures in which background and foreground images are obtained photographically from separate sources and subsequently combined to produce a completed picture on a single film medium. To obtain a satisfactory combination of the respective separately obtained photographic images, means must be provided to prevent overlapping of the respective image elements otherwise distortion and indefiniteness would result.
The art of traveling matte photography has been in use for several years for overcoming problems dealing with overlapping through the use of two basic systems. The primary objective of these systems is to produce a silhoutte of the foreground image or object in black against a clear field which is known as a traveling matte. This image or matte is placed in front of a background image and the two are photographed. The traveling matte prevents the background in the area of the foreground object from being recorded, thus leaving a hole for the foreground to be photographed on a subsequent exposure.
The most common system in use is commonly known as the blue screen technique. An actor or object is positioned in front of a translucent blue screen which is illuminated from the rear. The actor is lit normally and both are photographed onto standard motion picture film. Then, film undergoes a great many laboratory duplications and filtration to eliminate the blue tint of the screen and replace it with the background image. Inherent problems of this system have been the danger of blue light spilling on the actor or blue clothing, either one of which will render the actor transparent to the background in those areas so contaminated. The system is oftentimes costly and characterized by a cut-out look of the foreground object since soft edges and blur are difficult to maintain in the process.
The other system makes use of a beam splitting camera which is a camera that can photograph the same image on two strips of film simultaneously. Through the use of such a camera, one can produce the foreground against black on one film and its traveling matte on the other film. This is accomplished by the use of specially illuminated actors and screens coupled with film stocks which are in turn sensitive and insensitive to the particular wavelengths of light used for photography. Sodium vapor, infra-red, ultra-violet or similar light is used to illuminate the screen which is rendered black on one film and clear on the other depending on the respective films sensitivity to produce the aforementioned photographic elements. Although this system greatly simplifies the optical laboratory processes and produces excellent composites, its primary disadvantage resides in the requirement for a very specialized camera and exotic light sources. Also, the system is subject to changing improvements in film stocks which may suddenly become sensitive to the lights specifically designed to be invisible to the film.
Therefore, a long standing need has existed to provide an economical and relatively simple apparatus and method for taking single images and combining these separate images onto a single film medium without distortion or degradation of image quality.